Shapefiles

Edit the .sty files in the Style Files folder to change the thresholds. Each file has lines that look like this: Color: "CFCC" "H01" 25 0 0 205

The third item after Color:, above 25, is the threshold where the shapefiles will be shown.

I set the following thresholds on my files:

Hydrology: 25

Roads: 50

Trains: 25

Now that they're in place and tweaked, load them using GIS → Load ShapeFile. Pick a shape file, and then pick the matching style file (road with road, train with train, etc). Do this for each county you want.